Allen Ginsberg, a visionary writer and author, was also a photographer. An exhibit of his work is on display at the National Gallery of Art. (Photo courtesy of National Gallery of Art)

He saw “the best minds” of his generation” destroyed by madness and as “angel-headed hipsters burning for the ancient heavenly connection to the starry dynamo in the machinery of night.”

He was like an Old Testament prophet preaching in jeremiad poetry to post-World War II America. He was Allen Ginsberg, a visionary writer and author of the above famous opening lines of his celebrated poem “Howl.”

He was an anarchist at heart and anti-war activist, who would try by chanting to levitate the Pentagon in 1967, and avatar to his poetic muse the romantic poet Shelley who had called poets the unacknowledged legislators of mankind.

And he was the iconic poet of gay consciousness and sexual liberation of all men as possible brothers, and indeed as lovers. He channeled the “barbaric yawp” of that poet of free verse and gay affection, Walt Whitman.

But he was also a photographer. And it was Ginsberg, who died in 1997 at age 70, whose little-known treasure trove of photographs — taken of himself and other celebrated “Beat” writers such as Jack Kerouac and William S. Burroughs, among others, between 1953-1963 — forms the remarkable exhibit of some 80 black-and-white portraits in “Beat Memories: The Photographs of Allen Ginsberg,” on view now at the National Gallery of Art’s West Building through early September.

That Ginsberg was gay was never in doubt in “Howl,” his first big success in 1956, in which he sang of those who “purgatoried their torsos night after night, with dreams, with drugs, with waking nightmares, alcohol and cock and endless balls,” and in fact the poem is far more explicit about the particulars of fellatio and sodomy and yet from the very beginning it was hailed as a notable part of the new literary canon.

Eye-opening indeed, and so are this set of unself-conscious photographs that form an intimate vision of Ginsberg as a young man finding his way “to see the world in a grain of sand, and heaven in a wildflower” as one of those who inspired him the most, William Blake, once declared to be the object of poetry.

His postwar generation, including writers like Truman Capote and Norman Mailer, musicians Charlie Parker and Dizzy Gillespie, painters like Larry Rivers and Jackson Pollock, “celebrated an art that was full of rebellion, risk, and experimentation, and one that was highly expressive of their personal experience [and] … a romantic, almost heroic faith in their art and in its redemptive qualities,” says Sarah Greenough, the National Gallery’s senior curator of photographs and curator of this stellar exhibition.

They were soon hailed as “the Beats,” a term taken “from slang first used by jazz musicians and hustlers … to denote not only the down and out but also the physically and emotionally exhausted,” says Greenough.

“Wild child” Ginsberg, while briefly studying literature at Columbia University, famously found himself in Oedipal revolt against his teachers. Instead, Ginsberg followed other teachers — romantic poets like Shelley and sometimes opium-smoking symbolists like Rimbaud, Hart Crane and Dylan Thomas, and of course most of all Whitman, alive to all sensations in his “Song of Myself,” and all of whom Ginsberg called his “secret heroes.”

“What would Allen say? What would Allen say?” Greenough asked aloud about this exhibit in a preview opening of the show, which went public on May 2. And she imagined him answering while chanting in “his candid and even beseeching voice,” with his “deep appreciation for the vernacular and the power of perception.”

In fact the photographs were taken by Ginsberg almost nonstop as he carried his $13 Kodak camera everywhere in his peripatetic life, beginning in 1953 in Greenwich Village and later San Francisco and then “on the road” in Europe, India and Southeast Asia until he lost the camera in 1963 and with it also his interest in recording life as “snapshots” of what he called “certain moments in eternity” and “the sacredness of the moment.”

All along he simply showed them to friends and then tossed them as forgotten “keepsakes,” packages of negatives pushed to the back of a desk-drawer or shoved to the bottom of his closet, where they would remain ignored by him until the early 1980s. At that point, Ginsberg came to realize that he should show them to the world — reprinted and sometimes enlarged, with extensive written inscriptions added.

Ginsberg later said that they were “meant more for a public in heaven than one here on earth, and that’s why they are charming.”

In addition to photographing his lifelong lover and companion, Peter Orlovsky, as youthful and so sexually appealing, Ginsberg also recorded snapshots of the bisexual writer Jack Kerouac, with whom he was in love, and the older novelist William S. Burroughs.

Burroughs in fact lived with Ginsberg for three months and the younger man wrote that the novelist whom he saw as “the most intelligent man in America … fell in love with me and we slept together and I saw a soft center where he felt isolated, alone in the world.” Ginsberg later admitted he took advantage of their intimacy to “invade” Burroughs’ privacy and record him lying in bed, clad only in his underwear and glancing longingly toward him.

Such photos form the backbone of this exhibit, telling a story from his earlier life but also his later life, for he resumed taking pictures from the early 1980s until his death – revisiting people like Orlovsky and Kerouac later in their lives and new faces like Bob Dylan. See this exhibit for the narrative of a generation and the faces that depict it, in this first scholarly presentation through Sept. 6.

Greenough herself will give a public lecture based on her exhibit catalogue, including a book signing, at 2 p.m. Saturday, May 23. Gallery talks meanwhile will be offered by lecturer Diane Arkin at 11 a.m. on May 18 and 25, and June 1, 15, and 17.

Other events – held in the NGA East Building auditorium – include films:

• “Lowell Blues” (2000), celebrating Jack Kerouac’s early years and featuring actor Johnny Depp, musician David Amram, and poet Gregory Corso – 2 p.m. Saturday, June 26.

• “Patti Smith: Dream of Life” (2008), the documentary record of the punk singer, songwriter and poet and Beat avatar as recorded by filmmaker Stephen Sebring, 4:30 p.m. on Sunday, June 27.

Also, the NGA’s summer tradition, the “Jazz in the Garden” concert series, begins its 10th season on Friday, May 28 with weekly performances every Friday evening from 5 to 8:30 p.m. in the Sculpture Garden. In honor of the exhibit, the first concert, May 28, features be-bop jazz performed by female jazz vocalist Leslie Summey.